According to The Third Generation Partnership Project (3GPP) Technical Specification Group Radio Access Network, Requirements for Further Advancements for E-UTRA (LTE-Advanced), Release-10 (3GPP TR 36.913 V8.0.0 (2008-06)), Long Term Evolution—Advanced (LTE-Advanced) should target a downlink (DL) peak data rate of 1 Gbps and an uplink (UL) peak data rate of 500 Mbps. Comparing Long Term Evolution (LTE) (Release-8) to LTE-Advanced, the UL peak data rate has increased from 50 Mbps to 500 Mbps. An important component to enable such a dramatic throughput increase on the UL is the application of spatial multiplexing.
In a 3GPP LTE compliant communications system, a layer mapping defined for DL MIMO alternates the modulation symbols of a transport block (TB) between two layers if a TB is being mapped to two layers. However, the alternating nature of the mapping precludes advanced receiver algorithms, such as successive interference cancellation (SIC). Thus there is a need to define an improved layer mapping from that used in DL LTE Release-8, as well as for UL MIMO communications for LTE-Advanced.